Monday, November 28, 2011

Lab 10: Mitochondrial Eve

One could say she's the Mother of Modern Humanity and it would not be hyperbole. Mitochondrial Eve is where all Homo Sapien gets its mitochondrial dna. This tells us some very important things about humans, and enables science to trace our path from obscure North African tribe to the dominant species on Earth.

It's been a long road.

The reason we can trace our ancestry all the way back to the first modern human is Mitochondria, an organelle located in the cells of all humans. This small, bean-shaped organelle supplies energy to the cell for it to work more efficiently. We can use this to trace our lineage because of the unique Mitochondrial DNA inside the organelle, completely different from the rest of the cell's DNA. This information, unlike normal gene transfers which use both mother and father DNA, is purely matriarchal. One Hundred Percent of the DNA in a mitochondria is derived from the mother of the child. This gave scientists the ability to trace the path of humanity from it's first beginnings to it's spread across the entire globe (See map above).

If nothing, those little bean-shaped organelles have shown the scientific community that no matter how disparate we look and how different our languages are we are all from the same place and are part of the same family.

Lab 9: Dog Parks

When discussing Environmental Sciences it is important to remember the every day implications of humanity's interaction with nature. Dumping chemicals from a factory could ruin an entire watershed, clear cutting can erode away all fertile soil in an area and leave it barren, and what is the connection between the emissions from the cars that drive past your house and your garden in the back yard? Dog Parks are yet another scenario where Humans and Nature meet with unexpected consequences.

Socially, Dog Parks are a great way to allow your pet to get exercise, meet other dog lovers, and enjoy the outdoors. However, they are not immune to the environmental variables that affect so much of our daily lives. At the Macon Dog Park, for example, there is a small creek that runs through it. This creek is runoff from a neighborhood nearby, and is subject to contaminants from garbage on the side of the road, car exhaust, biological matter from other animals, and chemicals that might be dumped by an irresponsible person such as anti-freeze or motor oil.

Anti-freeze? In my water? It's more likely than you think.

To further delve into this topic, the dogs themselves are a risk to one another. Dogs attacking other dogs, dogs eating the feces of other dogs, dogs giving other dogs diseases, it's pandemonium. One of the largest threats to the safety of dogs in these large group gatherings is the Parvovirus. According to Wikipedia: "Canine parvovirus is a particularly deadly disease among young puppies, about 80% fatal, causing gastrointestinal tract damage and dehydration as well as a cardiac syndrome in very young pups. It is spread by contact with an infected dog's feces. Symptoms include lethargy, severe diarrhea, fever, vomiting, loss of appetite, and dehydration." It's important to take notice of such biological issues that could arise from something as simple as going to the dog park, as well as the environmental impacts that can shape and affect unsuspecting animals in even the most controlled of environments.

Lab 8: Darwin's Dilemma

The Burgess Shale is a fossil bed in the Canadian Rockies which contains one of the largest collection of fossils in the world, is known for having numerous soft-body fossils, and is one of the oldest at 505 million years old. This fossil collection gave science an unprecedented look into life in the Cambrian era, where macro-organisms first became prevalent on Earth and set the stage for later evolution into the creatures we know today.

The Cambrian Period is where large animals first took over the Earth, and it was an explosion of new types of life that had never before been seen. Where Pre-Cambrian biota was largely bacteria and some smaller hard-shelled creatures, the Cambrian was lush with many different types of creatures that we today would consider beyond bizarre.
Hallucigenia: A creature so strange it was first reconstructed upside down. There really is no modern analog to this strange Cambrian creature.

Charles Darwin studied the Cambrian Era as an undergrad at Cambridge in Whales, where the first Cambrian fossils were excavated. Throughout the crafting of his Theory of Evolution, Darwin acknowledged that the Cambrian Era posed particular challenges that had to be explained for this Theory to work properly. At the beginning of the Cambrian, there was an explosion of new life in a relatively short period, one that seems to be too short for evolution to work, and the extreme diversity of life cannot currently be accounted for using the Theory of Evolution. According to Darwin, life starts with a small number of phyla, and then diversifies over millions of years. But, in the Cambrian Explosion, the Earth went from a few crab-like creatures and bacteria to having an extremely diverse range of creatures with no real obvious explanation.  In the Prologue of Origin of the Species, Darwin admits that if there were to be a new discovery in paleontology to dispute his theory it would be from the Cambrian period, and that the diversity of life in the Cambrian would be a valid rebuttal of his ideas.

The Burgess Shale continues to pour a wealth of information into the scientific community, forcing us to constantly look and adjust our worldview about the origins of life on Earth and how we came to be. 

Monday, November 14, 2011

Lab 6: Jackson Springs

Jackson Springs Park, and the surrounding area, was the first suburb in Macon and is now a private park. Our main purpose was to explore the geological diversity of the area and learn a bit about the history of this place.

We began with a hike around the park, picking up different rocks as we went, and Dr. Rood explained some of the history of the Park. It was once huge, encompassing most of the neighborhood surrounding it as well as the Baconsfield shopping center. Slowly, land development encroached on the natural beauty of the area as stores went up. At the same time, the land was being subdivided into lots for home development, which removed many of the old trees in the area for space and for use as energy in homes. Now, the park is just a small sliver hidden away in the Jackson Springs suburb.

The rocks we found were varied and gave us a chance to compare many of the samples we'd seen in class. I myself found a very bright pink Feldspar, while some of my other classmates were able to pick out Gneiss, Granite, Slate, and during our adventure we were able to see the ground strata of the area due to erosion by a stream nearby. Overall, the lab gave me insight into the history of my own hometown, and we got to actually get hammers in our hands and open some rocks, which made identification of the rocks during the test much easier.